Insulation displacement connection (IDC) type cable connector and a method for assembling a cable thereto

ABSTRACT

An IDC type multi-conductor cable connector and method for assembling cable thereto. The cable connector has a plurality of contact terminals mounted in respective holes in a housing having a plurality of holes. The contact terminals each has a contact part provided at one end and an IDC type connection part provided at the other end thereof. The connector has means for temporarily holding the contact terminals in a position where the connection part of each terminal is exposed. The connector can be transported or delivered from the vendor in this state. A cable is assembled by IDC assembling to each exposed connection part. After the connection of the cables has been completed, the contact terminals are inserted further into their respective holes so that the connection parts become entirely covered. Such configuration eliminates the need for a cover, a component which is necessary for ordinary IDC type connector, and enables reduction in the size of the connector and in labor costs. Such housing may be used in modular form. By combining such modular housings, it is possible to construct various type of connectors merely by changing the case used to combine the modules. Such combined connectors are easy to wire at the interior portions of the cable connector. So, high packing density multi-contact connectors are provided.

BACKGROUND OF THE INVENTION

The present invention relates to a cable connector having a plurality of contacts for connection a multi-conductor cable. More particularly the invention involves a cable connector which is suitable for connecting cables thereto by the insulation displacement connection method and a method for assembling a cable and the connector.

Recent progress in the design of electronic equipment has increased the demand for small size cable connectors to which cables may be easily connected. A cable assembling method known in the art as the insulation displacement connection (IDC) method is increasingly being used. The IDC assembly method allows the cables to be connected to the connector without removing the insulation coating from the cables. In IDC assembling, a connection part is provided on the connector for connection to the cable. The connection part is provided with blades which pierce through the cable coating and bite into the core wire of the cable to make electric contact therewith when the cable is pressed to the terminal. So, connection of the cable to a contact terminal for the cable is accomplished by simply pressing the cable against the contact terminal.

Various type of connectors useful for IDC assembling have been developed. These have been classified into two types. The first type, as shown in FIG. 1, uses a contact terminal 1 which is fixed to the cable 2 by crimping, and then the contact terminal is inserted into a housing 3 of the cable connector and fixed therein by known means. An example of such connector is disclosed in U.S. Pat. No. 4,323,296 of I. Andoh. In this type of connector, the necessary number of contact terminals 1 must be prepared for each of the connectors. Such preparation is troublesome both for vendors and users who handle many such cable connectors.

On the other hand, as shown in FIG. 2, the second type of prior art connector is provided with contact terminals 1 mounted in a housing 3. The necessary number of contact terminals 1 are arranged in the housing 3, so the trouble mentioned above with respect to the first type of the connector is eliminated, and assembling of the cable 2 is accomplished simply by pressing the cable 2 into the contact terminal 1. However, in such an arrangement, the contact terminals 1 must be covered by a cover 4, because bare contact terminals are undesirable for safety reasons as well as reliability of the connector. This makes it difficult to reduce the size of the connector, and additional assembly time and equipment is required for fixing the cover 4 in position.

SUMMARY OF THE INVENTION

A general object of the present invention, therefore, is to provide a cable connector that is small in size and facilitates assembly of a cable therewith. More precisely, it is an object of the present invention to provide a cable connector which has contact terminals mounted in a housing in a manner suitable for IDC assembling, and wherein after the cable is assembled to the connector, there is no need for the contact terminals to be covered using a special cover.

Another object of the present invention is to provide a method for assembling the cable and said cable connector.

A further object of the invention is to provide a modular housing for the cable connector to enable fabrication of a variety of complex cable connectors by combining the modules.

According to the present invention, the cable connector is composed of metal contact terminals and a housing holding the terminals in position. First, each contact terminal is temporarily held by inventive spring action in a first position in the housing. In the first position of the contact terminals, a connector part of the contact terminal for engaging the cable is exposed by the housing. Thus, it is easy to press the cable into the connection part for connection thereto by IDC assembly. Such state is called the pre-load state, and the process for setting the contact terminals in such first position is hereinafter referred to as pre-loading. The cable connectors are supplied to the user in such pre-loaded state, therefore, the above mentioned problems, such as preparing the necessary number of the contact terminals for each connector, are avoided.

When the cable is pressed into the connection part, the blades formed on the contact terminal pierce through the insulation coating of the cable and bite the core wire of the cable to make electric contact therewith. At the same time, the holding members provided on the contact terminal embrace the cable to tightly affix the cable to the contact terminal. This is similar to the manner in which ordinary IDC assembling is accomplished.

When the fixing of the cable to the contact terminal is finished, the contact terminal is pushed into the housing and is fixed therein in a second position. In this second position, the connection part of the contact terminal which had been exposed by the housing during pre-loading is inserted into a hole in the housing, and it is entirely covered by the housing without using a special cover. At the same time, the other end of the contact terminal, which may be either a male or female cable connector, is put into a position to complete the formation of the cable connector.

By adopting such configuration, all of the problems described above are eliminated and a cover for the connection parts becomes unnecessary, whereby the size of the connector may be smaller than that of prior art connectors. Moreover, such configuration of the cable connector makes it possible to form the housing as a module, and by proper combination of the housing modules, it is possible to form various shaped cable connectors, such as flat or rectangular connectors, for example. It is also possible to vary the number of cables to be connected to the cable connector.

Furthermore, such configuration makes it easy to wire the cables into the connector, whereby a high packing density connector having a plurality of contacts is provided.

These and other objects and advantages of the invention will become apparent from the following detailed description of preferred embodiments taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a prior art cable connector wherein the contact terminals are inserted into the housing after the individual cables are fixed to respective contact terminals.

FIG. 2 shows another prior art type of cable connector, wherein the contact terminals are embedded in the housing.

FIG. 3 is an exploded view illustrating the overall configuration of a cable connector embodying the present invention.

FIG. 4(a) is a schematic sectional view taken substantially along line A--A' in FIG. 3, illustrating the first position and the second position of the contact terminal in the housing.

FIG. 4(b) is a front view of the housing seen from the direction of arrow B in FIG. 4(a).

FIG. 5 is a front view of a complex cable connector formed using three modules.

FIG. 6 is a partially cutaway perspective view of an embodiment of the present invention, illustrating the manner in which the housing modules and cables may be mounted in a case to form a complex cable connector.

FIGS. 7(a) and 7(b) are respective front and side elevation views schematically illustrating a machine for assembling cables to the cable connector of the present invention.

FIG. 8 is an enlarged perspective view of the machine of FIGS. 7(a) and 7(b) with parts broken away for illustrating the mechanism thereof.

FIG. 9(a) through (d) are schematic views illustrating the steps of assembling the cable to the cable connector.

Throughout the drawings, the same or similar reference numerals are used to designate the same or corresponding parts.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 3 illustrates an overall configuration of a cable connector embodying the present invention. The cable connector of the present invention is composed of contact terminals 1 for making electric contact to respective cable 2, and a housing 3 for mounting the contact terminals 1.

The contact terminal 1 is made of metal, copper alloy for example, and formed by stamping. One end of contact terminal 1 comprises a connection part 5 which connects with cable 2, while the other end of the contact terminal 1 comprises either a male or female jack 6 which engages with a corresponding female socket or male plug (not shown). This latter part 6 will be referred to hereinafter as a contact part. Contact terminal 1 is provided with a centrally located, elongated leaf spring 7. In FIG. 3, jack 6 is shown as a female jack, but it will be apparent that jack 6 may as well be a male jack. In the explanation hereinafter, the description will be carried on with respect to a female jack.

Connection part 5 is provided with blades 8 which pierce through the insulation coating 9 of the cable 2 when the cable is pressed toward the connector part 5, and the blades 8 bite into the core wire 10 of the cable 2 to make electric contact therewith. Connection part 5 is further provided with holding members 11, which are bent to embrace the cable to tightly fix it to the contact terminal 1. The shape and structure of connection parts, such as connection part 5, which are suitable for IDC assembly, and the shape of the male or female jack 6 are conventional, so further description is omitted for the sake of simplicity.

Housing 3 is made of an insulating material, plastic for example, and may be fabricated by injection molding for example. Housing 3 is formed to appear like an harmonica as shown in FIG. 3. FIG. 4(b) shows a front view of the housing 3, as seem from the direction of the arrow B in FIG. 3. As can be seen in FIG. 3, the upper wall 14 of housing 3 is cut away at one end of the housing so as to form a respective open deck 12 disposed in front of each opening or hole 15 into which the contact terminals 1 are to be inserted. The open decks 12 are separated from each other by partition walls 13. The length of each deck 12 is substantially equal to the length of the connection part 5 of the contact terminal 1. The widths of the decks 12 and the holes 15 are about the same as the width of the contact terminal 1, and the height of each hole 15 is slightly less than the height of holding members 11 before bending. Therefore, when contact terminal 1 is inserted into hole 15 with contact part 6 leading the way, the terminal does not go into hole 15 further than the position indicated by the reference character C in FIG. 3, where connection part 5 is exposed on the open deck 12. Such position is referred to as the first position.

A window 16 is provided in upper wall 14 of the housing adjacent each opening 15 as show in FIG. 3. Leaf spring 7 is initially disposed higher than the lowre surface of wall 14, but it can be compressed and bent downwardly by upper wall 14 as contact terminal 1 is pushed into hole 15. When contact terminal 1 reaches its first position, the distal end of leaf spring 7 is urged upwardly into window 16. Window 16 is positioned in upper wall 14 for catching spring 7 in such a manner, and when the end of spring 7 is thus engaged in window 16, the contact terminal 1 cannot be pulled out of the housing without first pushing spring 7 downwardly through window 16.

The relationship of contact terminal 1 and housing 3 can be seen more clearly in FIG. 4(a), which presents a cross-sectional view of the connector taken substantially along the line A--A' in FIG. 3. In FIG. 4(a), contact terminal 1' is shown at its first position in upper hole 15' while contact terminal 1" is shown at its second position in lower hole 15", a condition which will be described hereinbelow. It will be clear from FIG. 4(a) that contact terminal 1' is held in its first position by spring 7' is engaged in upper window 16' and by holding member 11' which is initially taller than height of hole 15'. Thus, contact terminal 1' is stopped by the holding member 11' and prevented from going further into the upper hole 15', and it is prevented from going backwards by spring 7'. The wording "upper" and "lower" are used to identify the parts in the FIG. 4(a). However, in practice, the upper and lower segments of housing 3 are formed similarly to each other, so the distinction between upper and lower is meaningless.

In the manner described above, each hole 15 of housing 3 may initially be provided with a respective contact terminal. The contact terminals 1 are initially temporarily held in their first positions. The insertion of contact terminals 1 into respective holes 15 of the housing 1 to their first positions is hereinafter referred to as pre-loading, and the state of the connector in such state is referred to as the pre-loaded state. The connector can be delivered to the user in such a pre-loaded state. Thus, neither the vendor nor the user need worry about the number of the contact terminals necessary for each cable connector. This is similar to the second type connector as described with reference to FIG. 2.

To assemble the cable and the connector, a cable 2 is first aligned with its corresponding deck 12 on which a contact terminal 1 is held in its first position, as shown in FIG. 3. Then the cable 2 is pressed downwardly onto the connector so that the blades 8 pierce through the cable coating 9 and bite into the wire 10 to make contact therewith. Contemporaneously, the holding member 11 is bent so as to embrace the cable. This process is similar to the conventional procedure for assembling cables in ordinary IDC type connectors. Since the holding members 11 are now bent, it is possible to push the contact terminal 1 further into the hole 15. So, as shown in FIG. 4(a), contact terminal 1" is pushed into lower hole 15" until the tip 17 of contact part 6" (female jack in this embodiment) reaches the end of lower hole 15" and spring 7" reaches lower window 18" and engages therein. As can be seen in FIG. 3, windows 18 are positioned in upper wall 14 of housing 3 so that they can catch the distal ends of spring 7 in such manner. Thus, contact terminal 1" cannot be pulled out of its second position without first pushing the end of spring 7" out of window 18". As can be seen in FIG. 4(a), windows 16 and 18 are of a size such that the distal ends of the springs 7 do not protrude out of the windows. This is important to insulate the contact terminals 1 from their surroundings. But the size of windows 16 and 18 must also be sufficient to prevent each terminal 1 from being pulled out of the corresponding hole 15 in which it is installed.

In like manner, the remaining contact terminals are assembled with their respective cables, and the cable connector is completed. As can be seen in FIG. 4(a), the height of holes 15 at the ends thereof remote from decks 12 (in the left hand side in the figure) is less than the height of holes 15 at their entrances adjacent decks 12 (right hand side). A slanted surface 14', 14" is provided between the larger and smaller portions of holes 15. This shape of the holes 15 is designed to accommodate the outside configuration of contact part 6. Thus, each contact part 6 is fixed precisely in a position in alignment with an opening 19 provided in the housing 3 to present a socket for an external lead. FIG. 4(b) illustrates the front view of the connector taken in the direction of the arrow B in FIG. 4(a).

In the embodiment of FIGS. 4(a) and 4(b), the connector has eight contacts arranged in two rows. But it will be clear that the arrangement of contacts may easily be varied and various modifications are possible. But from a practical view point, the arrangement of contacts as shown in the embodiment of FIGS. 4(a) and 4(b) is very convenient. If one arrangement, for example as shown in FIG. 4(b), is made a standard, its housing may be used as a module. By combining several such modular housings, it is possible to form further varieties of complex connectors. An example of such complex connector is shown in FIG. 5 which shows a front view of the complex connector as seen from its socket side. In this embodiment, three modular housings 3 are combined into a single unit by a shell 20. The combined complex connector has twenty four contacts arranged in four rows. If further modules are added on each side of this embodiment, a larger connector is provided. On the other hand, if only two modules are combined, the connector becomes a square having sixteen contacts. Further, if such modules are arranged in side by side relationship, a flat connector having two rows of contacts is provided. Other variations may be possible simply by varying the shell 20 to combine the modules in different ways.

FIG. 6 is a partially cutaway perspective view of such combined connector. In this embodiment, five modules 3 are packed in a shell 20, to provide forty contacts corresponding to the forty individual cables 2 of a multicable line 102. The shell 20 is divided into two parts, the upper shell 20' and the lower shell 20", which are joined by screws 22. After the wiring of the cables to respective housings has been completed, the housings are placed in proper position. A hook 21 is provided on the shell 20 to fasten the connector to the opposing socket or chassis (not shown). The construction of the shell 20 may be an ordinary one, and is not specifically related to the invention, therefore, further description is omitted for the sake of simplicity.

Usually, it is difficult to wire the individual cables to the inner parts of a connector having a large number of contacts. So, prior art cable connectors have been large in order to enable wiring of the terminals positioned in the interior portions of the connector. Another solution was to provide a flat type of connector. But by using the housing configuration provided by the present invention, it is easy to wire the cables to the interior portions of the connector, since each of the modules can be wired separated and then the same may be combined into a single unit. This makes it possible to provide a small size and high density connector that has many contacts.

A machine for assembling the cables to the cable connector will be described briefly hereinafter. FIGS. 7(a) and 7(b) show schematically an example of a machine designed for assembling the cable connector of the present invention. FIG. 7(a) is a front view of the machine and FIG. 7(b) is a side view of the machine schematically illustrating the relationship of the main parts of the machine. In FIGS. 7(a) and 7(b), the reference numerals 23 and 24 designate cable clampers. The cable clamper 23 is movable up and down to clamp the cable, and both cable clampers 23 and 24 are movable horizontally to push the contact terminal 1 into the housing. A cable guide 25 is provided with a taper 25' for guiding the cable to the assembly position. A punch 26 is provided for pressing the cable toward the contact terminal of the connector. The housing is loaded on a base 27 and hook 28 shifts the housing by the pitch of the terminal spacing after the wiring to each terminal is finished. A mechanism for moving these parts and a controller for controlling the timing and sequence of their respective motions are each installed in a case 29. As will be described below, the motions of these parts are simple and conventional, so a description of the mechanism for driving these parts is omitted.

The specific motions of the parts described in the foregoing paragraph will be described referring to FIG. 8 and FIG. 9. FIG. 8 is an enlarged perspective view with some parts broken away for illustrating the main parts of the assembling machine of FIG. 7. The housing 3 is mounted on the base 27 with the groove 30 formed on the upper and lower surface of the housing 3 aligned with a rail 31 formed on the base 27. The hook 28 holds one of the windows 18. So, the position of the housing 3 is fixed on the base 27. As mentioned before, the housing is pre-loaded with each contact terminal 1 at its first position. Though the cable guide 25 is broken away in FIG. 8, it is to be understood that the tapered parts 25' (FIG. 7) lead the cables 2 over the connection parts 5 of the contact terminals 1. A side view of this situation is illustrated in FIG. 9(a). The cable guide 25 is partially broken away in FIG. 9(a), but it is to be understood that guide 25 also fixes the axial position of cable 2 as illustrated. At the same time, the cable guide 25 holds the housing 3 pressing it toward the base 27.

Next, as shown in FIG. 9(b), the cable clamper 23 goes down. As can be seen in FIG. 8, the tip 33 of the cable clamper is concave, so it holds the cable 2 at center of the cable clamper 23. As seen in FIG. 8, there is a side projection 32 on the tip of the cable clamper 24, and the tip 33 and the side projection 32 are disposed on opposite sides of the cable 2 so that during operation, as shown in FIG. 9(b), the cable is held between the side projection 32 and the flat part 34 of the tip of the cable clamper 23. At the same time, the wire 2 is bent by tip 33 as shown in FIG. 9(b).

Successively, the punch 26 goes down as shown in FIG. 9(c). The tip of the punch 26 is provided with grooves 35 positioned to receive the blades 8 when the punch 26 pushes the cable 2 downward into the connection part 5 of the contact terminal 1. Since the tip of the punch 26 is concave as shown in FIG. 8, it bends the holding member 11 around the cable 2 so as to embrace the cable tightly.

Then, the punch 26 goes up as shown in FIG. 9(d). Following that, the cable clampers 23 and 24 move horizontally toward the housing 3. In practice, clampers 23 and 24 are disposed at a slight angle relative to housing 3, as shown in FIG. 9(d). Thus, the contact terminal 1 is pushed into the hole 15 of the housing and positioned at its second position as described before. As can be seen in FIG. 9(d), the contact terminal 1 is now entirely covered by the housing. In such a manner, the assembling of the wire to the cable connector is completed. And the machine goes back to the state as illustrated in FIG. 9(a). The cable guide 25 frees the housing, and the hook 28 shifts the housing 3 by one pitch of the wiring. Then, the wiring for the next terminal begins.

The wire assembler described above is but an example, and it will be possible for one skilled in the art to design various types of such machines. Although the machine itself is not included in the scope of the invention, it must be pointed out that by adopting the configuration of the cable connector of the invention and applying an assembly method as disclosed above, it becomes very simple to assemble the cables to the connector. There is no need for preparing the necessary number of contact terminals for each of the cable connectors, and there is no need to worry about the contact terminals coming loose during transportation of the connector. Since, a cover for the contact terminals is unnecessary, the size of the cable connector is further reduced, and machines, equipment and labor for fitting such cover are elimated. Accordingly, the costs of asembling machines and labor are saved. This has great merit both from the view point of the vendor and the view point of the user of the connector. 

We claim:
 1. A cable connector having a plurality of contacts to be engaged with respective counterpart of opposite connector, said cable connector comprising:plurality of contact terminals made from metal each of which being provided with,a contact part provided at one end of said contact terminal for contacting to corresponding terminals of opposite connector, and a connection part provided at another end of said contact terminal for connecting cable thereto; a housing made from insulator for holding said contact terminals, said housing being provided with holes corresponding to each contact terminals for holding them separated from each other; and a pre-loading means for holding said contact terminals at a first and second position in said hole in the housing, in said first position said connection part of said contact terminal is exposed from the hole of said housing, while in said second position said connection part of said contact terminal is entirely covered by wall of said hole in the housing.
 2. A cable connector according to claim 1, wherein said pre-loading means comprises:a nail spring provided at center part of said contact terminal and the height of said nail spring is higher than the height of the holes in the housing to which the contact terminal is inserted; a first window which is formed on wall of said housing, and is positioned so as to receive said nail spring when said contact terminal is inserted into the hole of said housing and placed in the first position; and a second window which is formed on wall of said housing, and is positioned so as to receive said nail spring when said contact terminal is inserted into the hole of said housing deep to the second position.
 3. A cable connector according to claim 1, wherein said connection part comprises:more than one blades formed integrally with said contact terminal, said blade pierces through cable coating to bite core wire of said cable to make electric contact to it when the cable is pressed to said connection part; and more than one holding members formed integrally with said contact terminal, said holding member is bent for embracing the cable to tightly hold the cable when the cable is connected to said connection part of said contact terminal, and the height of said holding members before it is bent is higher than the height of said hole in the housing into which the contact terminal is inserted.
 4. A cable connector according to claim 1, wherein cross section of said hole in the housing is made smaller at its deeper part compared to its entrance part by tapering at middle part of said hole so as to tightly contact with the outside of said contact part of said contact terminal when it is inserted deep into the second position.
 5. A cable connector according to claim 1, wherein said housing further comprises cut away parts where upper walls of said holes are cut away providing open decks at each opening of said holes, each of said open decks is extend along the axis of said hole and is separated from each other by partition walls, the length of said cut away part is substantially equal to the length of said connection part, and the width of said cut away part is substantially equal to the width of said contact terminal.
 6. A cable connector having a plurality of contacts to be engaged with respective counterpart of opposite connector, said cable connector being composed of plurality of modules and a shell to combine the modules in one cable connector, said module comprising:plurality of contact terminals made from metal each of which being provided with,a contact part provided at another end of said terminal for contacting to corresponding terminals of opposite connector, and a connection part provided at one end of said contact contact terminal for connecting cable thereto; a housing made from insulator for holding said contact terminals, said housing being provided with holes corresponding to each contact terminals for holding them separated from each other; and a pre-loading means for holding said contact terminals at a first and second position in the hole in said housing, in said first position said connection part of said contact terminal is exposed from the hole in said housing, while in said second position said connection part of said terminal terminal is entirely covered by wall of said hole in the housing.
 7. A cable connector according to claim 6, wherein said pre-loading means comprises:a nail spring provided at center part of said contact terminal, and the height of said nail spring is higher than the height of the holes in the housing to which the contact terminal is inserted; a first window which is formed on wall of said housing, and is positioned so as to receive said nail spring when said contact terminal is inserted into the hole of said housing and placed in the first position; and a second window which is formed on wall of said housing, and is positioned so as to receive said nail spring when said contact terminal is inserted into the hole of said housing deep to the second position.
 8. A cable connector according to claim 6, wherein said connection part comprises:more than one blades formed integrally with said contact terminal, said blade pierces through cable coating to bit core wire of said cable to make electric contact to it when the cable is pressed to said connection part; and more than one holding members formed integrally with said contact terminal, said holding member is bent for embracing the cable to tightly hold the cable when the cable is connected to said connection part of said contact terminal, and the height of said holding members before it is bent is higher than the height of said hole in the housing into which the contact terminal is inserted.
 9. A cable connector according to claim 6, wherein cross section of said hole in the housing is made smaller at is deeper part compared to its entrance part by tapering at middle part of said hole so as to tightly contact with the outside of said contact part of said contact terminal when it is inserted deep into the second position.
 10. A cable connector according to claim 6, wherein said housing further comprises cut away parts where upper walls of said holes are cut away providing an open deck at each opening of said hole extend along said hole, said open decks are separated from each other by partition walls, the length of said cut away part is substantially equal to the length of said connection part, and the width of said cut away part is substantially equal to the width of said contact terminal.
 11. A method for assembling a cable to a cable connector having plurality of contact terminals mounted in a housing which has plurality of holes to insert respectively said contact terminals, said contact terminal having a contact part provided at one end and a connection part provided at another end of said contact terminal, wherein the method for assembling the cable comprises steps of:step A, inserting said contact terminal into said hole in said housing leaving said connection part exposed from said hole; step B, connecting the cable to said connection part exposed from said hole; and step C, inserting said contact terminal which is connected to said cable by the step B, further deep into the hole of said housing until said connection part of said contact terminal is entirely covered by wall of said hole in the housing.
 12. A method for assembling a cable to a cable connector according to claim 11, further comprising following step D which is performed between said steps A and B:step D, inserting said contact terminals respectively into all of said halls in the housing, and temporally fixing them each of which leaving said connection part exposed from said hole, enabling to transport the cable connector in this state.
 13. A method for assembling a cable to a cable connector according to claim 11, said step B comprises:pressing said cable to said connection part of said contact terminal, to pierce through cable coating by more than one blades formed integrally with said contact terminal and bite core wire of said cable to make electric contact to it. 